The present invention relates to an image processing system, projector, program, information storage medium and image processing method having a lens shift function and a zoom function.
In order to display an appropriate image from an image projecting device such as a projector, it is necessary for the image projecting device to perform the adjustment of view angle (zoom adjustment), the adjustment of image display position and so on.
In general, however, the adjustment of view angle and adjustment of image display position are performed by a user. This is very troublesome for the user.
In addition, there is a case that an image is distorted to create a so-called keystone distortion in the vertical or horizontal direction depending on the relative angle between the optical axis of a light projected from an image projection device such as a projector and an object onto which the light is projected, such as a screen.
For such a reason, the image projection device must project an image after its distortion has been removed.
However, the general image projecting device having a distortion correcting function includes an inclination sensor which can only correct the distortion of an image in the vertical direction, but not in the horizontal direction.
Moreover, the distortion in the horizontal direction has been semi-automatically corrected based on information provided when a user has indicated four corner points on a screen through a mouse. It is troublesome for the user to indicate the four corner points on the screen through the mouse.
To solve such a problem, for example, Japanese Patent Laid-Open No. 2000-241874 has proposed an automatic image positioning method in a projector, comprising the steps of projecting a predetermined test pattern from the projector onto a screen; using a monitor camera to capture the image of the test pattern on the screen; and analyzing the image data of the captured test pattern image to adjust the focus of the projector. The automatic image positioning method of Japanese Patent Laid-Open No. 2000-241874 displays the projected image on the screen at its center by projecting a rectangular all-white image on the screen as a test pattern image, sensing the all-white image through the monitor camera to detect the position of the screen within the all-white image, using a projection lens having a scaling function to enlarge or reduce the projected image until it reaches the end points of the screen, and adjusting the depression and elevation angles in the projection lens. Furthermore, the automatic image positioning method of Japanese Patent Laid-Open No. 2000-241874 adjusts the keystone distortion of the projected image by calculating the adjusted value of the keystone distortion based on the positions of the end points in the screen and all-white image.
However, in such a technique of Japanese Patent Laid-Open No. 2000-241874 that the angle of view is adjusted by using the scaling function of the projection lens to enlarge or reduce the projected image until it reaches the end points of the sensed screen, the process takes much time. Furthermore, the technique of Japanese Patent Laid-Open No. 2000-241874 cannot be applied to a case where the aspect ratio of the screen is different from that of the projected image. Additionally, Japanese Patent Laid-Open No. 2000-241874 describes the adjustment of the image display position by adjusting the depression and elevation angles of the projection lens to display the projected image on the screen at its center, but does not concretely disclose how the process has been performed.
Moreover, in the technique of Japanese Patent Laid-Open No. 2000-241874 where the adjusted value of the keystone distortion is calculated based on the positions of the end points in the screen and all-white image and, for example, if the screen is square, the correction of the keystone distortion will be carried out while the projected image remains distorted.
When the projector or the like is to project and display an easily viewable image, it is required to display the image more largely and also to project the image more highly after the adjustments of view angle, image display position and image distortion have been performed.